Subject: Re: [PATCH 1/1] Fix detection of pwritev support for OSX.
From: Sergey Shinderuk <s.shinderuk@postgrespro.ru>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: James Hilliard <james.hilliard1@gmail.com>,
 pgsql-hackers@lists.postgresql.org, Thomas Munro <thomas.munro@gmail.com>
References: <20210119111625.20435-1-james.hilliard1@gmail.com>
 <479372.1611070041@sss.pgh.pa.us>
 <CADvTj4riiHN9Zhhk5qOVndevQMOxuduFbFVVJnCiQ4R7k5_eng@mail.gmail.com>
 <480660.1611071845@sss.pgh.pa.us>
 <CADvTj4o6LEGRJSRR4H8Rmn8r_vv4ZE_mS0MS5Z60NwDZRwdZHQ@mail.gmail.com>
 <483800.1611076636@sss.pgh.pa.us>
 <CADvTj4oD6NoTe78vLi+Ss1CFuPH26vrhUrVTd5DHAPX63vP9Ww@mail.gmail.com>
 <522433.1611089678@sss.pgh.pa.us>
 <CADvTj4qNyMM5vHo+uZ6Xfq5n5g++X_bUTX1-g3zmNXYDWAo8sQ@mail.gmail.com>
 <CADvTj4pucOvo6aWinatLgARs3mjPFSiAXZr2ErSG4ASJsKNxBw@mail.gmail.com>
 <559755.1611106628@sss.pgh.pa.us>
 <CADvTj4qcwzrti9qK8E_xnoPHHn13hWqOGQC-1r3a=Y=mmGvCfQ@mail.gmail.com>
 <791992.1611184078@sss.pgh.pa.us>
 <CADvTj4qJmUdvVw3ECGK_FXXjkTneo5gVJGSvtpDxGrrseQdXDw@mail.gmail.com>
 <915981.1611254324@sss.pgh.pa.us>
 <CADvTj4pzBHOa4PyzLKxZrnOiuwYTa2CDYU=4nUB3Dh8BoReQPg@mail.gmail.com>
 <6d43a157-e51a-6449-0b47-94d133829afc@postgrespro.ru>
 <1166796.1611335531@sss.pgh.pa.us>
 <49989a13-49d2-935a-c651-74719ec565e6@postgrespro.ru>
Message-ID: <5a274baf-8b68-5249-502a-1c31f45b7cee@postgrespro.ru>
Date: Sat, 23 Jan 2021 08:12:16 +0300
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0)
 Gecko/20100101 Thunderbird/78.6.1
MIME-Version: 1.0
In-Reply-To: <49989a13-49d2-935a-c651-74719ec565e6@postgrespro.ru>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 23.01.2021 08:02, Sergey Shinderuk wrote:
> I checked the script [1], and it really requires the CLT. Here is the 
> explanation [2] for this:
> 
>      There is actually no such requirement. However, there are
>      formulae that will be forced to build from source if you do not
>      have the CLT. They can still be built from source with Xcode
>      only, but because the pre-built bottles are compiled in an
>      environment that has both Xcode and the CLT installed, there are
>      some cases where the bottles end up having a hard dependency on
>      the CLT. A major example is gcc. So installing the CLT may help
>      you avoid some lengthy source builds.
> 
>      We ensure that all Homebrew formulae can be built with Xcode.app
>      alone. Most formulae can be built with just the CLT, and those
>      that require the full Xcode.app have an explicit depends_on
>      :xcode => :build. Some users would prefer to use only the CLT
>      because it's a much smaller download and takes less time to
>      install and upgrade than Xcode.


In the gcc formula [1]:

   # The bottles are built on systems with the CLT installed, and do not 
work
   # out of the box on Xcode-only systems due to an incorrect sysroot.
   pour_bottle? do
     reason "The bottle needs the Xcode CLT to be installed."
     satisfy { MacOS::CLT.installed? }
   end


I guess this is the "xcrun --show-sdk-path" thing we've alredy disccussed :)


[1] https://github.com/Homebrew/homebrew-core/blob/master/Formula/gcc.rb#L36

-- 
Sergey Shinderuk
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company